Re: [Performance regression] BCM4359/9 on S905X2

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> On 21 Mar 2023, at 2:46 pm, Jerome Brunet <jbrunet@xxxxxxxxxxxx> wrote:
> 
> 
> On Tue 21 Mar 2023 at 11:40, Marc Gonzalez <marc.w.gonzalez@xxxxxxx> wrote:
> 
>> Hello everyone,
>> 
>> I've been benchmarking an Amlogic S905X2 board.
>> It provides a BCM4359/9 WiFi chip connected through SDIO.
>> 
>> There's a large performance gap between vendor kernel and mainline.
>> (Downloading a 1GB file to /dev/null from a device inches away)
> 
> The title is misleading. You are comparing different sources. This is
> not a regression. This is merely a difference.
> 
> If we are talking about mainline, then which board is it ? What is the
> corresponding DT ? What is the MMC configuration in both case ? Have
> you checked you are running with the same clock configuration to begin
> with ?

[snip]

https://github.com/torvalds/linux/blob/master/arch/arm64/boot/dts/amlogic/meson-g12a-sei510.dts#L428

^ this device-tree (based on other chat with Marc)

To Jerôme’s point; unless you’ve tweaked it upstream will be running
at 100MHz and the vendor kernel will be 200MHz, and maybe with other
high-speed modes activated. Most upstream device-trees are running a
conservative/safe configuration at 50MHz to avoid past speed-related
issues. As stability has improved over time most boards could be run
at faster speeds, but ‘performance’ is such subjective topic that it
would probably need a large amount of testing to convince people to
change the current defaults. That said (FWIW) I’ve bumped all boards
in my tree that consume the gx-p2xx-q2xx dtsi to 100MHz without any
attributable issues being flagged by users.

Christian





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